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J. S. CAMPBELL.

DENTAL VULCANIZING .PLASKS.

Patented July 12, 1881.

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UNITED STATES JOHN S. CAMPBELL, OF NEW YORK, N. Y.

DENTAL VULCANIZING-FLASK.

SPECIFICATION forming part of Letters Patent No. 244,031, dated July 12,1881.

Application filed June 11, 1881.

To all whom it may concern:

Be it known that I, J. S. CAMPBELL, a citizen of the United States,residingin the city, county, and State of New York, have inventedcertain new and useful Improvements in Dental Vulcanizin g-Flasks, fullydescribed and represented in the following specification, and theaccompanying drawings forming a part of the same.

My invention relates to an improvement in dental flasks; and it consistsin the means herein described for closing the flask obliquelyviz., aninclined guide secured to one part of the flask and operating againstthe opposite part as the parts approximate in closing.

It also consists in the combination of an inclined and perpendicularguide, for the purpose set forth.

In the drawings annexed, Figure 1 is a side view of a flask providedwith the ordinary perpendicular guide 9, the entire right-hand side ofthe flask being shown in central section, to exhibit the mold and thecelluloid or rubber blank. Fig. 2 is a plan of the flask shown in Fig.3, which is a side elevation, showing auxiliary guides applied to thefront and rear of the flask. Fig. 4 is a side elevation of a flaskprovided with removable guides. Fig. 5 is a side View of a flask havingthe guide-pins bent; and Fig. 6 is apart plan of the same, showing theshape of the guide ear or lug.

In flasks provided with the ordinary guidepins g, (shown in Fig. 1,)theparts of the flask, lettered A A in the drawings are necessarily limitedto a movement perpendicular to their parting-line 1. Such a movement isquite appropriate in many cases, but in packing a plate upon an undercutbed, such as is shown at B in Fig. 1., great difficulty arises inforcing the plate (indicated at P) to its proper position between thetwo parts of the mold shown in section at B and 0. Much difficulty isalso experienced in separating the parts B and O by a perpendicularmovement, to remove the wax model when the bed is undercut, as at 6,upon one part, and the opposed corner, as at d, is hooked under by theconformation of the model, for in such cases the natural movement of theparts separated would be parallel with the undercut line at e. As theperpendicular guides usually employed do not afford (No model.)

such a movement, the plaster above the undercut part is frequentlybroken and the mold destroyed. The perpendicular guides also prevent theupper half of the mold, when formed with a hooked corner, as at d, fromhearing equally upon the blank plate P and pressing it into uniformcontact with all parts of the bed B. Upon the contrary, the corner (Ibears forcibly upon the blank at its front side and pushes it backwardas the mold closes, in consequence of which the front part of the moldis imperfectly supplied with material for a perfect plate, while therear part is overcrowded with an excessive amount.

My invention obviates these difficulties in operating upon undercutmodels by providing the flask with an inclined guide in place of theperpendicular ones heretofore employed, the inclination of the guideenabling the operator to execute all ordinary work with equal ease,while it affords him special facility for treating unusual cases.

My improved flaskis'also especially adapted for the production of rubberplates inlaid with celluloid upon the front, as in such work a movementof the cover 0 and the blank P toward the undercut face 0 affords agreater pressure at that particular point, and secures a closer unionbetween the two substances forming the plate.

It is obvious that an inclined guide could be obtained by merely tippingthe guide-pins g toward the front of the flask and inclining the lugs hat a similar angle; but as it is desirable to have the final movement ofthe cover A perpendicular to the bottom A, it is preferable to have aguide capable of producing or aifording both such movements; and I havetherefore shown three modes of constructing theinelined guide to securean oblique movement of the cover until the flask is nearly closed, andthen to permit the action of a perpendicular guide, by the aid of whichthefinal pressure is more uniformly distributed than if the cover movedto its final position in an oblique direction.

In all the figures the inclined guide is lettered a, and theperpendicular guide I), and the two are separately applied in the viewshown in Fig. 3, and combined in the constructions shown in Figs. 4: and5. In these three views the flask is represented as partly opened, orready for the pressure in the vulcanizer. Under such conditions the toppart of the flask, A, is shown moved a little to one side of the bottom,A, and the top is shown in contact with the upper end of the inclinedguide. This guide is shown in Fig. 3 as a stud projecting from the sideof the bottom part, A, and beveled or inclined at an angle to the jointin the flask at 1. Two projecting pins, 2', upon the upper part, A,embrace the stud a, and guide the top of the flask as it moves downwardwhen closing, and similar pins f embrace a perpendicular stud, b, at theopposite side of the flask to keep that side in position, and to guidethe flask perpendicularly when it is nearly closed.

It is obvious that with this construction the flask may be movedperpendicularly during its entire closing movement, for the pins embracethe studs only upon two sides, so that the flask may be slid backwardwhen first adjusted in contact with the rear pin, 1), and be guided bythat instead of the inclined one a.

Short guide-pins fitted in cars upon the flask, similarly to those shownat g in Fig. 1, maybe used, in connection with the inclined guide, todirect the last part of the closing movement.

In Fig. 4 both guides are combined in a single round pin, which isconstructed to operate upon lugs h similar to those in Fig. 1; but thepin is adapted to furnish an inclined guide by having its rear sidebeveled or inclined to the desired angle. A part of the pin near itsbase is left cylindrical, to afford a perpendicular movement to theflask at that point, and the hole in the upper or guide lug, h, isproperly fitted to the cylindrical portion. In the figure the upper halfof the flask A is shown moved forward, with the rear part of the hole jin contact with the inclined side of the pin; but it is obvious that thehole could be placed in contact with the perpendicular side of the pin,if desired, to close the flask perpendicularly. The pin is shown screwedinto the lower lug, h, for convenience of removal when opening the flaskupon the wax model; but as the removable pin has been made the subjectof a. separate application by me, I have not claimed it herein.

In Fig. 5 the inclined and perpendicular guides are shown united in abent pin, a, secured to a lug upon the part A and bearing upon a lug, h,on the part A, the lug havinga slot, a, formed in its 'front side,toembrace the pin like the pins z' in Fig. 3.

From the above description it will be plain that my inclined guide maybe applied to a flask so as not to interfere with a perpendicularmovement when desired, and that it may be combined with a perpendicularguide, either in the same piece or one attached elsewhere upon theflask.

In Fig. 5 the perpendicular guide is shown as an ear or pin projectingupward from the lower lug, h, to operate against the rear of the lugcontaining the slot 0; but it may be arranged elsewhere or dispensedwith entirely, if preferred.

I do not therefore limit myself to the precise construction shown,asother modes of carrying it out may be devised; but

I claim my invention as follows:

1. In combination with a two-part dental flask, an inclined guidesecured to one part of the flask and operating to move the other partobliquely to its final position when closing, substantially as and forthe purpose set forth.

2. The combination, in a two-part dental flask, of an inclined guide, asa, and a perpendicular guide, as b, the two guides operating to directthe flask when closing, substantially as and for the purpose set forth.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

JOHN S. CAMPBELL.

Witnesses:

J 0s. A. CRISTADORO, THos. S. CRANE.

